This invention relates to the provision of an oil reservoir to regulate the amount of oil in a sump for a scroll compressor.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a pair of scroll members each have a base and a generally spiral wrap extending from the base. The wraps interfit to define compression chambers. One of the two scroll members is caused to orbit relative to the other, and as the two orbit relative to each other, the size of the compression chambers decreases, compressing an entrapped refrigerant.
Scroll compressors are typically mounted within a sealed housing. Oil is supplied from a sump near the bottom of the housing upwardly through a drive shaft to the relatively moving surfaces. The oil lubricates the relatively moving surfaces and returns to the sump through an oil return tube.
It is desirable to have a good deal of lubricant for the relatively moving surfaces. However, providing a higher lubricant level does raise some design challenges. As an example, a scroll compressor is typically provided with a lower counterweight which may extend downwardly into a high oil level. As the counterweight rotates within the oil, there are efficiency losses.
For the above reason, it may sometimes be desirable to trap the oil in a reservoir such that the counterweight will be secluded or shielded from the reservoir. However, such a reservoir can raise design challenges if it is not able to adjust the amount of lubricant stored in the reservoir in response to the overall lubricant level. As an example, if the oil level is low for some reason, it would not be desirable to trap a large amount of lubricant within the reservoir, as there may then be insufficient lubricant for lubricating the relatively moving surfaces.
In the disclosed embodiment of this invention, a lubricant reservoir is provided adjacent the lower end of the motor for a scroll compressor. The lubricant reservoir is provided with an orifice which meters lubricant back to the main sump. During operation with a relatively high level of lubricant, the lubricant retained in the reservoir will provide a lower overall oil level such that the counterweight is not rotating within the lubricant level. Generally, the returning lubricant will be maintained in the reservoir until the reservoir becomes full. Some lubricant will be returned to the main sump through the metering orifice. Further, if the level is sufficiently high, other lubricant may spill over the top of the reservoir and return to the main sump. Preferably, all of this returning lubricant will be sufficiently separated from the path of the counterweight such that the above-referenced efficiency losses will not occur.
At a lower lubricant level, the metering orifice will ensure that the oil is returned to the main sump, and that a large amount of oil is not stored in the reservoir. Thus, the present invention provides an oil reservoir which is self-regulating such that during low lubricant levels, the reservoir stores little or no lubricant such that available lubricant is directed into the main sump for lubricating the relatively moving surfaces.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.